Windows 7 has become the biggest-grossing pre-order in Amazon's history – worth even more than the most recent JK Rowling book, Harry Potter and the Deathly Hallows.

"The launch of Windows 7 has superseded everyone's expectations," the managing director of Amazon.co.uk, Brian McBride, said. "Demand is still going strong."

Millions of computer users will be getting their first taste of Microsoft's latest operating system tomorrow, when Windows 7 goes on sale worldwide.

The American software company is pinning high hopes on the launch, which aims to be a hit with PC owners and erase the problems suffered by its predecessor, Windows Vista, when it hit the market in 2007.

Vista came in for heavy criticism when it was plagued with problems soon after its launch, but signs are encouraging for Windows 7 so far.

Reviews have been largely positive, and high street retailers say they anticipate strong sales of the software.

PC World is opening its shop in London's Tottenham Court Road at midnight for the launch, offering customers the chance to get their hands on the upgrade and receive advice on how to make the most of the software's new features.

The makeover promises a string of upgrades and improvements for Windows users, including a more streamlined interface, better performance, and reduced power requirements, which means laptops with better battery life.

It also incorporates new features that work with touchscreen displays – a move the company hopes will spur PC makers to develop new computers and all-in-one systems that take advantage of the growing interest in multitouch interfaces inspired by mobile phones.

The success of Windows 7 is being seen as crucial for Microsoft, which is pumping millions of dollars into an advertising campaign and other initiatives aimed at boosting sales and awareness.

Among them is a sponsored half-hour TV show written by Seth Macfarlane, the creator of American television series Family Guy, which the company hopes will broaden its appeal with younger consumers when it is broadcast in the US in November.

Microsoft even plans to open its own chain of branded shops to help push sales of Windows 7 and other products – starting with two in the US - mirroring the move that has helped propel rival Apple to stellar success in recent years.

Microsoft's Bill Veghte told the Guardian earlier this year that it was vital the company "put the magic back" into Windows, which runs 93% of the world's computers.

"The problem for Microsoft wasn't that products like Vista were bad," he said. "It's that the company wasn't telling its story well enough."

But Microsoft is not the only company with heavy investment in making sure Windows 7 is a success. The makeover is also crucially important for the wider PC industry, which has experienced significant slowdown in sales as shoppers have chosen not to buy new computers during the recession.

Manufacturers such as Hewlett Packard, Dell and Sony have witnessed a decline in sales that they are desperate to reverse. They hope that Windows 7 will encourage consumers to buy new machines that will be better able to take advantage of some of the software's features.

Not everybody will be rushing to buy, however. Most businesses are expected to take at least a year to test Windows 7 and decide whether to upgrade, while consumer groups have suggested that the public should remember the problems with Windows Vista, which proved to be incompatible with millions of add-ons such as printers and digital cameras when it went on sale in 2007. Microsoft has worked hard to make sure Windows 7 does not suffer the same problems, but John Bogue of Which? Computing said that it could be better for shoppers to hold on and make sure that all of their peripherals work well with the new system.

"Software bugs are par for the course for newly-released programs, and operating systems are no exception," he said. "Unless you like downloading patches and updates, we recommend waiting a year."